Performance of a hybrid central venous catheter utilized for both peripheral blood stem cell harvest and transplant support of patients undergoing autologous peripheral blood stem cell transplantation.

Patients undergoing autologous peripheral blood stem cell transplantation (PBSC) frequently require the sequential insertion of two central venous catheters, one for leukapheresis and one for transplant support. Hybrid catheters suitable for leukapheresis and long-term use have been increasingly used, but there is limited information regarding their performance and complication rate. The purpose of this study was to determine the performance of the Pheres-Flow hybrid catheter when utilized for both leukapheresis and transplant support, with particular emphasis on the incidence of infectious and occlusive complications. We prospectively analyzed the performance of 92 catheters in 82 consecutive patients who underwent autologous peripheral blood stem cell (PBSC) transplantation. Occlusion was the most frequent complication of this catheter with 29% of the patients experiencing difficulty drawing blood or infusing fluids. Infection was another frequent complication. Twenty-two percent of patients developed catheter-related bloodstream infections and 15 catheters had to be removed because of proven or suspected infection that did not respond to antibiotic therapy. Nevertheless, 77% of patients were able to complete leukapheresis and transplant support with only one catheter. We conclude that the utilization of the Pheres-Flow catheter for both leukapheresis and transplant support is feasible, but that new strategies need to be developed to decrease the incidence of occlusive and infectious complications of hybrid catheters.

Transjugular intrahepatic portosystemic shunt: accuracy of helical CT angiography in the detection of shunt abnormalities.

PURPOSE: To determine the sensitivity, specificity, and accuracy of helical computed tomographic (CT) angiography in the detection of transjugular intrahepatic portosystemic shunt (TIPS) stenoses or occlusions. MATERIALS AND METHODS: Thirty-seven patients underwent 50 helical CT angiographic examinations and, within 2 weeks of each examination, portography with measurement of the portosystemic pressure gradient. Helical CT angiograms were independently interpreted by three radiologists who were blinded to the results of portography. Results of helical CT angiography and portography were compared. Sensitivity and specificity of helical CT angiography were separately calculated for the demonstration of morphologic abnormalities and the determination of their hemodynamic significance. RESULTS: Of the 50 portograms, 31 (62%) demonstrated morphologic TIPS abnormalities, 24 (77%) with and seven (23%) without elevated portosystemic pressure gradients. Helical CT angiograms correctly demonstrated 30 (97%) of the 31 morphologic abnormalities and allowed correct diagnosis of 22 (92%) of the 24 hemodynamically significant abnormalities. Nineteen (38%) portograms were normal; helical CT angiograms correctly demonstrated the absence of abnormality in 17 (90%) of these cases. Sensitivity and specificity of helical CT angiography for all morphologic abnormalities were 97% and 89%, respectively, and, for hemodynamically significant abnormalities, 92% and 77%. CONCLUSION: Helical CT angiography holds promise as a screening modality for the detection of TIPS stenoses or occlusions.

Polytetrafluoroethylene-encapsulated stent-grafts: use in experimental abdominal aortic aneurysm.

PURPOSE: To evaluate expanded polytetrafluoroethylene (ePTFE) encapsulated stents for the treatment of aortic aneurysms with emphasis on the blood and tissue-material interactions. MATERIALS AND METHODS: Experimental aortic aneurysms were created in dogs by enlarging the aortic lumen with an abdominal fascial patch. Twenty animals underwent endoluminal repair after allowing the surgically created aneurysm to heal for 2 months prior to transluminal aneurysmal exclusion. The device used consisted of an 8-cm-long ePTFE encapsulated stent graft. The animals were killed in groups at 1 week and at 1, 2.25, 6, and 12 months. Specimens were processed for histologic and luminal surface studies. RESULTS: Before the animals were killed, aortography demonstrated two thrombosed aortae in the 6-month group and two endoleaks in the 12-month group. Endothelialized neointima extended into the proximal and distal portions of the prosthetic lumen, with minimal cell coverage in the center of the graft. The overall percent surface area covered by endothelialized neointima was 22% +/- 6% at 6 months and 18% +/- 10% by 1 year (P = .75). Histologic examination demonstrated minimal tissue penetration into the ePTFE. CONCLUSION: Transluminal exclusion of abdominal aortic aneurysms by encapsulated stent-graft is easily accomplished. With this device, tissue coverage and penetration of the stent graft is limited and does not tend to increase with time.

Oral contraceptives and venous thromboembolism: a case-control study designed to minimize detection bias.

BACKGROUND: Previous epidemiologic studies of venous thromboembolism and oral contraceptive use are susceptible to bias in the detection of venous thromboembolic events. This case-control study uses a unique design to minimize the influence of detection bias. METHODS: Nonpredisposed women younger than the age of 40 years who underwent pulmonary angiography, lower extremity venography, or lower extremity duplex Doppler sonography at a large urban hospital were classified into a case group or control group based on results of their diagnostic studies. Medical records were reviewed for a history of current oral contraceptive use. RESULTS: Fifty-seven women met the study criteria during the 11-year study period. Seven of 9 women in the case group and 17 of 48 women in the control group were currently using oral contraceptives (odds ratio 6.38; 95 percent confidence limits 1.19, 34.2). CONCLUSIONS: The association previously noted between venous thromboembolism and oral contraceptive use is not due to bias in the detection of venous thromboembolic events.

PIP: Both case-control and cohort studies have consistently documented an association between oral contraceptive (OC) use and venous thromboembolism risk. However, since OC users undergo closer medical surveillance than non-users, these studies are susceptible to detection bias. To overcome this potential source of bias, the present study used a new case-control study design in which 234 women under 40 years of age with suspected deep vein thrombosis or pulmonary embolism recruited from University Hospital in San Antonio, Texas, during 1983-94 underwent contrast venography, pulmonary angiography, or duplex Doppler ultrasound examination. 127 of these women were subsequently excluded from the study because of predispositions to venous thromboembolism. The 9 women whose test results were positive comprised the case group, while the 48 with negative findings served as controls. 7 of the 9 cases and 17 of the 48 controls were current OC users (odds ratio, 6.38; 95% confidence interval, 1.19-34.2). Although documentation of the OC brands women were using was sparse, 12 of the 13 women for whom these data were available were using OCs containing 35 mcg or less of estrogen. The findings of this analysis indicate that the documented association between OC use and venous thromboembolism is not a result of detection bias. The use of women undergoing diagnostic procedures to form both the case and control groups should be replicated in larger populations and diverse settings. The study design could be further strengthened by collecting data on OC use prospectively and uniformly, before women undergo diagnostic procedures.

Transjugular intrahepatic portosystemic shunts: assessment with helical CT angiography.

To evaluate diagnostic computed tomographic (CT) angiograms of transjugular intrahepatic portosystemic shunts (TIPS), helical CT angiography was performed in 10 patients with (n = 7) or without (n = 3) shunt dysfunction. CT angiography was performed with 3-mm-thick sections, pitch of 1, 120 kV, and 180-220 mA, after injection of 150 mL nonionic contrast material at 5 mL/sec, with a 50-second scanning delay after initiation of injection. All patients underwent transjugular portography within 1 week after CT angiography. In all cases, CT angiography correctly showed the presence or absence of the abnormality. These preliminary data suggest that CT angiography can provide diagnostic images of normal and abnormal TIPS.

Jejunal phlebectasia presenting with massive gastrointestinal hemorrhage.

Our case report illustrates the clinicopathologic features of this rare vascular lesion and highlights that phlebectasia should be considered as a cause of gastrointestinal bleeding of undetermined etiology in adult patients.

Aortoiliac aneurysms: management with endovascular stent-graft placement.

PURPOSE: To evaluate endovascular stent-graft placement for management of aortoiliac aneurysms. MATERIALS AND METHODS: Balloon-expandable stents covered with polytetrafluoroethylene were placed in 11 aortoiliac lesions in nine male non-surgical candidates (mean age, 63.5 years). There were six abdominal aortic aneurysms, four iliac artery aneurysms, and one acute pseudoaneurysm from a ruptured iliac artery. Stent-grafts were dilated up to 14 mm (iliac) and 24 mm (aorta). Patients underwent follow-up computed tomography and angiography. RESULTS: Stent-grafts were successfully placed in all 11 cases. There were two complications: a ruptured iliac artery treated with placement of an additional covered stent and a lower-extremity vessel embolization and bowel infarction resulting in death. All stent-grafts remained patent without increased aneurysmal diameter. Three leaks (27%) were detected. Two leaks were treated with placement of additional covered stents. One still is asymptomatic. CONCLUSION: Endovascular treatment of aortoiliac aneurysms with stent-graft devices may be an alternative to surgery.

Improvement of thrombocytopenia due to hypersplenism after transjugular intrahepatic portosystemic shunt placement in cirrhotic patients.

Thrombocytopenia secondary to hypersplenism is a well-known complication of portal hypertension. The effects of transjugular intrahepatic portosystemic shunt (TIPS) on hypersplenism have not been adequately studied. In this report, we describe 11 patients who had significant improvement in their thrombocytopenia due to hypersplenism after TIPS. There was a statistically significant improvement in the platelet counts after TIPS placement, in virtually every case during the follow-up period, although some patients had platelet counts less than 100,000/mm3 at the end of the follow-up period. Statistically significant hemodynamic improvement in the gradient pressure was observed immediately after TIPS. Furthermore, all patients tolerated the procedure well, and TIPS-related complications were encountered during the follow-up period. Our data suggest that TIPS is an effective, noninvasive alternative to surgical interventions in the management of hypersplenism in cirrhotic patients, who are generally high-risk surgical candidates.

Transumbilical intravascular retrieval of an umbilical artery catheter.

We present a rare case of a broken umbilical artery catheter retrieved via a transumbilical approach with biopsy forceps.

Use of stents covered with polytetrafluoroethylene in experimental abdominal aortic aneurysm.

PURPOSE: To establish the effectiveness of covered stents in the treatment of aortic aneurysms, to investigate the histopathologic healing patterns of the device, and to determine the long-term endurance and integrity of modified polytetrafluoroethylene (PTFE). MATERIALS AND METHODS: Experimental aneurysms were created in dogs by enlarging the aortic lumen with a patch of abdominal fascia. After 5 months, eight animals underwent an endoluminal bypass. The bypass device consisted of a 6-cm-long stent covered with thin PTFE. After surgery, the animals were killed at 3, 6, and 12 months in groups of three, three, and two, respectively. Specimens were processed for luminal surface studies and cross-sectional histologic study. Explanted PTFE material was analyzed for its physical characteristics and performance and was compared with retained control samples. RESULTS: Before the animals were killed, aortography showed patent bypass conduits in all animals, although two of eight had leaks into the aneurysmal sac. Endothelialized neointima largely covered the luminal surface of the PTFE stent. The percentage of prosthetic surface covered by tissue did not change from 3 months to 1 year. Physical testing of the explanted PTFE material showed no structural deterioration and no change in the internodal distance. Thickness and axial tensile strength varied 12% and 17% from controls, respectively. CONCLUSION: Thin-walled PTFE seems to have physicochemical characteristics that make this material adequate for endovascular use. Though limited, this study supports the establishment of preliminary clinical evaluation of metallic stents combined with PTFE for the treatment of abdominal aortic aneurysm.

Transjugular intrahepatic portosystemic shunt placement for variceal bleeding: predictors of mortality.

PURPOSE: To identify factors that predict survival in patients with variceal bleeding who have undergone transjugular intrahepatic portosystemic shunt (TIPS) placement. PATIENTS AND METHODS: TIPS was performed in 64 of 65 patients. Indications were bleeding esophagogastric varices in 64 patients and hemorrhoidal bleeding in one. Child-Pugh classifications were A in two patients, B in 32, and C in 31. Acute bleeding was controlled before TIPS in 26 patients in stable condition but not in 39 patients whose condition was unstable. RESULTS: Twelve patients died within 30 days of TIPS, and another 14 died thereafter. The cumulative survival rate was 67% at 6 months and 56% at 1 year. Cumulative 30-day survival was 96% for stable and 69% for unstable patients, a significant difference (P = .0135). Thirty-day survival was 91% for patients in Child-Pugh classes A and B combined and 71% for patients in class C (P = .042). CONCLUSION: Efforts to control acute bleeding and improve a patient's metabolic status before TIPS are likely to improve 30-day survival.

Influence of anatomic distribution of atherosclerosis on the outcome of revascularization with iliac stent placement.

PURPOSE: To determine the influence of clinical and angiographic variables, including the anatomic disease pattern, on the outcome of iliac stent placement. PATIENTS AND METHODS: The 455 patients of the study population were divided in three groups according to the anatomic distribution of their peripheral atherosclerosis lesions. Pattern type 1 (focal aortoiliac and/or common iliac lesion) included 180 patients (39.6%), type 2 (external iliac lesion) comprised 58 patients (12.8%), and type 3 (multilevel lesions) included 217 patients (47.7%). RESULTS: Complete relief of symptoms immediately after revascularization was observed in 88.3% and 85.4% of patients with pattern type 1 and 2, respectively, compared to 60.1% with type 3 (P < .05). The persistence of clinical benefit at 36-month follow-up was 91.6%, 97.9%, and 60.8% in disease patterns 1, 2, and 3, respectively. The overall 1-year mortality rate was 3% with type 1 lesions, 5.7% with type 2, and 9.7% with type 3. On multivariate logistic regression, the presence of a disease pattern type 3 was the most powerful indicator (P < .001) of early unsatisfactory clinical outcome in iliac stent placement. Unexpectedly, female gender was predictive of unsatisfactory clinical outcome (P < .01) and higher periprocedural complications (P < .001) following iliac stent revascularization. CONCLUSIONS: Pattern type classification helps identify patients at higher risk for cardiovascular morbidity and mortality. Ideal candidates for iliac stent placement are patients with pattern type 1 or 2 disease.

Iliac artery stent placement with the Palmaz stent: follow-up study.

PURPOSE: The long-term efficacy of iliac artery stent placement with the Palmaz stent was evaluated for treatment of limb ischemia. PATIENTS AND METHODS: Iliac stent implantation for limb ischemia was performed on 108 limbs in 83 patients. Eighty patients (96.4%) were followed up clinically from 1 to 70 months (mean, 25.8 months), and 30 patients (37.5%) were followed up with angiography from 1 to 48 months (mean, 10.4 months). Patients were classified into six categories by using an ischemic ranking profile. Clinical success was defined as a minimum one-category improvement from preprocedure ranking. RESULTS: The clinical success rate was 98.9% immediately after the procedure and 86.2% at 48 months. Long-term success was statistically more common in patients with higher preprocedure and lower postprocedure ischemic ranking, and in patients without diabetes. Arteriography demonstrated a primary patency rate of 87.5% at latest follow-up, with five occlusions (12.5%) and only two (5.0%) restenoses. Average stenosis was 17.8% at 6 months and 24.7% at 2 years. Stent restenosis was statistically more common with a higher postprocedure pressure gradient. The complication rate was 9.7%, and 30-day mortality was 1.2%. CONCLUSION: Long-term clinical and angiographic follow-up demonstrates iliac artery stent placement with the Palmaz stent is safe and efficacious for treatment of limb ischemia.

Vascular occlusion with a balloon-expandable stent occluder.

PURPOSE: To evaluate the effectiveness of a new vascular occlusion device. MATERIALS AND METHODS: The device was created by coating a balloon-expandable stent with a silicone sleeve that tapers to a blind-ended nozzle at its leading end. Once crimp-mounted on an angioplasty balloon catheter, the device is introduced over a guide wire through a small end hole in the nozzle. RESULTS: The device was tested for stability and occlusive ability. No migration was measured over a pulsatile pulse range of 50-300 mm Hg, and mean flow rate in the occluded vessel was reduced from 443 mL/min +/- 99 (standard deviation) to 1.9 mL/min +/- 2.7. Subsequently, 12 arteries were occluded in three dogs, and immediate vascular occlusion was achieved in all vessels. An arteriovenous fistula was created in another six dogs and was successfully occluded with the device. Follow-up arteriography at 3 months demonstrated persistent occlusion with no migration of the device. CONCLUSION: This new occlusive device offers immediate vascular occlusion with excellent stability.

Stenting of the iliac arteries with the Palmaz stent: experience from a multicenter trial.

Balloon-expandable, intraluminal stenting of the iliac arteries with the Palmaz stent was the subject of a multicenter study for 4 years. A total of 486 patients underwent 587 procedures. Four hundred and five patients had unilateral and 81 had bilateral iliac stent placements. Follow-up ranged from 1 to 48 months (mean 13.3 +/- 11 months). Sustained clinical benefit of the treated patients was obtained in 90.9% at 1 year, 84.1% at 2 years, and 68.6% at 43 months. Angiographic patency rate was 92%. Diabetes mellitus and poor runoff had significant negative influence on the clinical outcome. The 10% incidence of procedural complications was not altered by operator experience.

Intraluminal bypass of abdominal aortic aneurysm: feasibility study.

This study evaluated the feasibility of treatment of abdominal aortic aneurysm (AAA) by means of intraluminal bypass. Artificial aortic aneurysms with fusiform Dacron conduits were created at surgery , a weft-knit Dacron tube with balloon-expandable stents attached at both ends was inserted transfemorally through a 14-F introducer sheath and expanded at the aneurysmal level by means of inflation of a coaxial balloon. The transluminal bypass successfully excluded the aneurysmal lumen immediately after placement. In two dogs, a postplacement aortogram revealed torsion of the graft that caused early occlusion. The six other dogs had a patent bypass at 6 months follow-up. Four of these dogs had evidence of kinking of the graft as a result of shrinkage of the prosthetic aneurysm. Histopathologic studies revealed that endothelialization was complete on the stents and partial on the graft surface. It is concluded that transluminal bypass of AAA is feasible in the dog model.

Gastrointestinal bleeding: treatment with gastrointestinal arterial embolization.

Retrospective analysis of 36 embolization procedures in 29 patients with gastrointestinal bleeding was undertaken, and the presence or absence of coagulopathy was identified as a major factor affecting embolization outcome. Embolization was successful in 18 of 29 (62%) patients and unsuccessful in 11 (38%). Eight of 11 failures (73%) occurred in patients with a coagulopathy, whereas three patients (27%) in whom embolization was successful also had a coagulopathy. Embolization was 2.9 times more likely to be unsuccessful (P = .0463) and death from bleeding after embolization was 9.6 times more likely to occur (P = .0065) in patients with a coagulopathy than in those without. Because embolization was successful in six of 14 (43%) coagulopathy patients, the authors advocate embolization in patients with gastrointestinal bleeding and coagulopathy, while all efforts to correct the coagulopathy would be made as early as possible.

Aortic bifurcation stenosis: treatment with intravascular stents.

Balloon-expandable intravascular stents were employed to correct atherosclerotic stenosis of the aortic bifurcation. The devices were placed in the proximal iliac arteries with the cephalic end of the stents contacting in the midline. This arrangement provided an adequate lumen for the distal portion of the aortic wall and the proximal iliac arteries. Six of seven patients who received this form of treatment had hemodynamic and clinical improvement of their vascular insufficiency at an average follow-up of 1 year.

Subselective embolization with gelatin sponge through an open-ended guide wire.

Subselective embolization was performed in 15 patients with the use of gelatin sponge injected through a 0.038-inch open-ended guide wire. Eight patients were being treated for acute bleeding, and seven underwent elective embolization of tumors (hepatic, pelvic, spinal) or arteriovenous malformations. The procedure was successful in all 15 patients, and there were no major complications. The open-ended guide wire can be used safely and effectively in selective embolization with gelatin sponge. It is more flexible than the 3-F Teflon catheters and less expensive than the 2.2-F tapered catheters now being used for this purpose.